

A001111


Number of inequivalent Hadamard designs of order 4n.


1




OFFSET

1,4


COMMENTS

In other words, number of 2(4*n1,2*n1,n1) symmetric designs.


REFERENCES

Spence, Edward; Classification of Hadamard matrices of order 24 and 28. Discrete Math. 140 (1995), no. 13, 185243.


LINKS

Table of n, a(n) for n=1..8.
R. K. Guy, Letters to N. J. A. Sloane, JuneAugust 1968
Spence, Edward; Hadamard matrices
Index entries for sequences related to Hadamard matrices


CROSSREFS

Sequence in context: A246307 A269588 A048658 * A133079 A116916 A080332
Adjacent sequences: A001108 A001109 A001110 * A001112 A001113 A001114


KEYWORD

nonn,hard,nice,more


AUTHOR

N. J. A. Sloane.


EXTENSIONS

a(8) from Brendan McKay, Feb 11 2012


STATUS

approved



